FOXBOROUGH, Mass.—Rob Gronkowski underwent surgery Monday morning for a broken left forearm suffered in the fourth quarter of Sunday's 59-24 win over the Colts. A league source said it isn't a season-ending injury but did not have a timetable for his return.

Gronkowski was blocking on the game's final extra point when Colts corner Marshay Green rushed him. Gronkowski's arm seemed to bend awkwardly and when he walked off the field it hung limp by his side.

Gronkowski is a big part of New England's offense because he is such a matchup problem for defenses, especially when he runs seam routes and in the end zone, using his big body and basketball background to post up defenders.

Aaron Hernandez isn't the same kind of player, but New England kept Hernandez on the sidelines Sunday with an eye toward Thursday night's matchup with the Jets.

Hernandez has been nursing a sprained ankle suffered against the Cardinals in Week 2. He came back against Seattle in Week 6 and played against the Jets in Week 7, but suffered a setback. Though he has been practicing, Hernandez hasn't played since. The Patriots didn't want to have him play Sunday and then again Thursday and risk another setback.

Offensive coordinator Josh McDaniels spent the spring drawing up ways to use the versatile Hernandez, who can line up basically anywhere on the field and is a tough cover for defenses, though for different reasons than Gronkowski.

We've seen Tom Brady have success with far inferior talent than he has now, even without Gronkowski, so the expectation is that there shouldn't be a huge dropoff once the necessary adjustments are made.

The vastly improved ground game certainly helps, since Brady hasn't had to do everything himself this season, thanks to the emergence of Stevan Ridley and Danny Woodhead's success as a third-down back.

Another option is Visanthe Shiancoe. New England signed the veteran in the offseason and he missed the first eight games of the season as the team's designated-for-return injured reserve player.

Shiancoe played in 26 snaps against the Colts after playing in just nine the week before but has yet to record a reception. Bill Belichick has said Shiancoe is both a blocker and a receiver, so he could also help fill the void. The Patriots also have Daniel Fells at the position, though he was a healthy scratch Sunday.